Posterior interchangeable tooth and backing for bridgework



D. S. HIGHKIN. POSTERIOR INT-ERCHANGEABLE TOOTH AND BACKING FOR BRIDGVEWORK. v

APPLICATION FILED FEB'. 10, 1920.

,7 8.. Patented Aug. 3, 19m

. l4 "1 um: 14 /6 /6 3 23 W a w 23 /8 lTED STATES PATENT OFFICE.

DAVID s. HIGI-IKIN, or BALTIMORE, MARYLAND.

Application filed February 10, 1920.

To all whom it may concern:

Be it known that I, DAVID S. HIGHKIN, a citizen of the United States, residing at Baltimore, in the State of Maryland, have 'invented certain new and useful Improvements in Posterior Interchangeable Teeth and Backings for Bridgework, of which the following is a specification.

The present invention relates to bridgework, and the object is the provision of a practical and effective structure involving porcelain tooth facings and metallic back ing, which will eliminate a relatively great amount of work in the production, willsave metal, and will permit the ready interchange of the porcelain facing elements when broken or injured without the necessity of removing the bridge or abutments.

In the accompanying drawings Figure 1 is a plan view of the novel backing element of the present invention.

Fig. 2 is a front elevation of the same.

Fig. 3 is a sectional viewon the line 33 of Fig. 2.

Fig. 4 is a plan view of thQPOIOfilELlH facing element.

Fig. 5 is a rear elevation of the same, and

Fig. 6 is a side elevation.

Fig. 7 is a view in elevation of the mesial side of the assembled facing and backing.

Fig. 8 is a longitudinal sectional view therethrough, showing the facing element partially removed.

Fig. 9 is a front elevation of a bridge formed with the facings in place thereon.

Fig. 10 is a view similar to Fig. 8, but on an enlarged scale in order to illustrate the details.

Similar reference numerals designate corresponding parts in all the figures of the drawings. r

The backing element in the present em bodiment is preferably of the usual material, gold, and consists of a downwardly tapered body having the upper portion in the form of a boxing. Thus the distal wall is designated 9, the opposite mesial wall 10, and the rear or lingual wall 11. The said rear wall, as shown, comprises angular sections, the lower portion of which is designated 12. It will be noted that the upper end portions of the walls 9, 10 and 11 are substantially at right angles to each other, forming a boxing having open front face, as 13. The bottom of this boxing is formed by oppositely disposed substantially horizontal Specification of Letters Eatent.

Patented A11 3, 1920.

Serial No. 357,543.

shelves 14 and the rear internal shoulder 15, the same inclosing the upper end of a dovetail socket 16 that is downwardly tapered, as shown in Fig. 3, the bottom of the socket being preferably convexed, as illustrated at 17. t will be noted that the front ends of the shelves or shoulders 14 terminate short of the front edges of the side walls 9 and 10. I

The tooth or facing element consists of the front portion 18 having the usual buccal surface corresponding to the natural tooth configuration. It is also provided at its upper end with an integral rear extension 19, the upper face of which corresponds in f rm and appearance to the natural tooth configuration. The portions 18 and 19 are connected by an integral brace portion 20 of downwardly tapered dovetail formation, and adapted to fit in and fill the socket 16. The extension 19 extends on opposite sides of the brace, forming shoulders 21 that rest upon the shelves or shoulders 14, and the brace 20, as shown in Figs. 6 and 7 terminates short of the rear end of the extension 19, formin a shoulder 22 that rests upon the shoulder 15. The front portion 18 furthermore is provided with oppositely extending flan es 2-3, and said flanges overlap thefront edges of the walls 9 and 10, completely covering the same.

It. will be obvious that a number of the backings may be soldered together and connected to abutments as 24 in Fig. 9, and that the facings may be placed in position therein, as indicated in said figure.

There are many advantages for the structure disclosed. In the first place, it will be noted that the backing is a relatively light shell, so that a comparatively small amount of metal is needed in its structure. Because of its shape, however, and the angular disposition of the parts, it is extremely strong and rigid, so that it is'not liable to become injured or misshapen. The facing element can be readily placed in position, and when in place, is interlocked with the backing, so that it cannot move forwardly and become displaced. Consequently when cemented in position, it will be rigidly held by reason of its interlocking engagement with the backing. It is to be noted particularly by reference to Fig. '7 that the front portion 18 of the facing element extends a considerable distance below the backing and below the lower end of the brace 20. This leaves surparticular gum of the patient or person to which the bridgework is applied, and it will be evident that a material amount of grinding can be effectedwithout affecting the relation of the parts, and particularly the brace that also'constitutes the interlocking connection with the backing. It will furthermore be noted that when the facing is in place, it is effectively supported at all points, the flat shoulders on opposite sides of the brace insuring relatively broad surfaces, andpressure due to mastication and biting being effectively resisted, and only tending to force the dovetail brace into the socket more tightly. Horeover it will be observed that the backing is substantially concealed, the rear extension havingithe appearance of the natural tooth and the front edges of the backing being covered by the flanges 23 of the facing. Furthermore the boxing surrounding the upper edge of the porcelain facing constitutes a guard that will avoid to a'very great extent the danger of chipping and breakage. In case of injury to the porcelain facing, however, it will be obvious that it can be readily removed from the backing without removing the bridge or its'abutments, and a new facing can bereadily ground to shape and fitted in place. The structure therefore not only eliminates much work that is necessary in the production of the usual bridgework, but this is also true of repairs. 7

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In dental bridge work, a supporting backing of metal having a socket that opens through its front face and through its outer end, said outer end constituting a boxing and a porcelain tooth facing having a projection on the outer portion of its rear side that fits in the outer portion of the socket and is inclosed by the boxingof the backing,

said projection having its end face exposed to biting action, and a reinforcing brace between thelfacing and extension and integral therewith.

2.. In dental bridge work, a supporting backing having a socket opening through its front face and through its top, said backing having outstanding walls forming a boxing, the interior of which is of greater width than the socket, forming internal supporting shoulders on opposite sides of the same and V a removable tooth facing having an upper rear extension that is inclosed by theboxing and rests on the shoulders, and a reinforcing brace between the facing and top extension, said brace extending into the socket between the shoulders. V

3. A backing comprising upper lingual, mesial and distal walls forming a boxing, opposite interior supporting shelves on the inner sides of the mesial and distal walls, and a tooth facing having a rear upper extension that fits within the walls and having shoulders that rest on the supporting shelves.

4. A backing comprising upper lingual, mesial and distal walls forming a boxing, opposite interior supporting shelves on the inner sides ofthe mesial and distal walls, and a tooth facing having a rear upper extension that fits within the walls and having shoulders that rest on the supporting shelves, said facing having opposite flanges covering the front edges of the mesial and distal walls.

5. A backing comprising upper lingual, mesial and distal walls forming a boxing, opposite interior supporting shelves on the inner sides of the mesial and distal walls,

7 and a. tooth facing having a rear upper extension that fits w1th1n the walls and having shoulders that rest on the supporting shelves, said backing having an undercut socket extending between the shelves, and said facing having an undercut brace that fits into the socket and interlocks the facing and backin 6. A backing comprising upper lingual, mesialand distal walls forming a boxing, opposite interior supporting shelves on the inner sides of the mesial and'distal walls, and a tooth facing having'a rear upper extension that fits within the walls and having shoulders that rest on the supporting shelves, said facing having opposite flanges coveringthe front edges'of the mesial and distal walls, said backing having a downwardly tapered dovetail socket extending between the shelves, and said facing having a downwardly tapered brace extending to the extension and detachably interfitting in the socket. r

' portion having flanges longitudinally along its opposite side faces that extend transversely of and project beyond the opposite side faces of the rearwardly extending portion to cover the front edges of the backing. In testimony whereof I afiix my signature.

DAVID S. HI'GHKIN. 

